Process for the treatment of phenolated industrial effluent

ABSTRACT

The present invention relates to a process for the complete purification of industrial effluent polluted by phenolated impurities wherein the degradation of the polluant is obtained by the action of an oxidizing reagent containing the HSO5 anion. The oxidizing reagent is a member of the group constituted by monopersulphuric acid and its salts. The oxidizing reagent is an aqueous solution containing HSO5 anion and containing furthermore NH4 , HSO4 ions and, optionally, alkaline cations. The oxidizing reagent is an aqueous solution containing the HSO5 anion and containing furthermore hydrogen peroxide and H , HSO4 and SO4 ions.

United States Patent 1 1 Zumbrunn et a1.

' [75] Inventors: Jean-Pierre Zumbrunn, 95 Saint Gratien; FrancoisCrommelynck, 69 Lyon, both of France [73] Assignee: LAir, Liquide,Societe Anonyme Pour LEtude Et LEx'ploitation Des Procedes GeorgesClaude, Paris, France 22 Filed: May 8,1972

21 Appl.No.: 251,102

[30] Foreign Application Priority Data May 13, 1971 France ..71 17293 52us. Cl ..2l0/63 51 1m. (:1 ..C02c 5/04 [58] Field of Search ..2l0/50,59, 63

[56] References Cited UNITED STATES PATENTS 2,311,314 2/1943 Reichert etal ..2l0/5O 1 51 Jan. 16, 1973 3,510,424 5/1970 Zurnbrunn ..210/63 OTHERPUBLICATIONS Eisenhauer, H.R., J.WPCF, 1964,36, p.1 1 16-1 128.

Primary Examiner-Michael Rogers Attorney-Alvin Browdy et a1.

[57] ABSTRACT The present invention relates to a process for thecomplete purification of industrial -effluent polluted by phenolatedimpurities wherein the degradation of the polluant is obtained by theaction of an oxidizing reagent containing the HSO; anion. The oxidizingreagent is a member of the group constituted by monopersulphuric acidand its salts. The oxidizing reagent is an aqueous solution containing1-180 anion and containing furthermore Nl-ifi, HSO; ions and,optionally, alkaline cations. The oxidizing reagent is an aqueoussolution containing the 1-180; anion and containing furthermore hydrogenperoxide and H, H80; and SO; ions.

18 Claims, N0 Drawings PROCESS FOR THE TREATMENT OF PHENOLATEDINDUSTRIAL EFFLUENT Thepresent invention relates to a process for thecomplete purification of industrial effluent (industrial sewage,industrial residual water) by destruction of the phenols andhydroxylated aromatic compounds substituted on the core by electrondonor groups, in solution. In this process, the phenols and othercompounds are degraded by oxidation to products which have lost thearomatic character of the pollutant and are, consequently, very muchmore readily bio-degradable.

Phenolated residual water is found in the effluent of gasworks, cokingplant, refineries, chemical synthesis works (manufacture and conversionof phenols), works manufacturing plastics materials (phenoplasts) and,in general, works in which there are processed coal, tars and theirderivatives, pesticides, dyestuffs, etc.

The residual phenol concentrations vary widely, depending on thespecific industry concerned. They may attain several grams per literNow, it is known that the phenols are toxic to fish at levels as low as0.1 mg/l. Furthermore, in water which is to be rendered drinkable by theaddition of Javel water, a phenol content as low as 0.01 mg/l willsuffice to impart an extremely disagreeable taste thereto, due to theformation of chlorophenols it is thus necessary to process such water,in order to eliminate the phenols therefrom.

Hitherto, the processes for the purification of phenolated water havenot been very numerous and, above all, they have not been totallyeffective. These known processes may be classified in accordance withtwo large categories.

First of all, the processes involving physical recuperation orelimination, operation either by liquidliquid extraction by means of asolvent, steam distillation, absorption on active charcoal or on anionexchanger resin, or by a foaming process whereby a surface-activeagent is added to the water and the phenol accumulates in the foam.

Then, among the best known processes involving chemical and biologicaldestruction, there may be mentioned treatment by activated sludges andbacterial beds. Depending on the nature of the biological bed employed,it is possible to purify effluents of initially 50-100 mg/l of phenol(such as may issue from an installation for physical recovery such asthose enumerated hereinabove) and to expel after several hours waterwhich still contains some mg/] of phenol. Some extremely elaborateplants make it possible to go down as far as 0.2-0.5 mg/l, but only bydint of extremely strict monitoring of the composition of the water tobe treated (pH, concentration in respect of phenol and foreign bodies,poisons of the bacterial bed).

It has also been proposed to effect oxidation treatment by ozone orpermanganate these two products are extremely costly the second resultsin the production of large quantities of sludges.

Treatment by chlorine may be considered to be interesting, but itfrequently produces chlorophenols and this almost always opposes theachievement of the desired aim, which is precisely to avoid theformation of such by-products.

Treatment by means of catalysed hydrogen peroxide is also known.

Apart from the chemical oxidation processes, all the other processes arenever quantitative and always leave a certain i'esidual phenol contentranging between 0.2 and several mg/l.

It is clear that a complete purification process has long been soughtafter, and numerous publications attest this fact. Among the latter,there has been mention of that relating to the oxidation of phenols bythe couple hydrogen peroxide and a salt of ferrous iron (ironll),conventionally known as the Fenton reagent it acts on the organiccompounds through intermediary of a highly oxidizing HO radical.

The reaction proposed by the authors (H.R. Eisenhauer, 1. WaterPollution Control Federation, 1964, 36, lll6to 1128) is as follows Thismode of proceeding for the purification of effluent is among the mosteffective. In fact, the purificaw tion achieved is complete andrelatively rapid Unfortunately, this process has some disadvantages,i.e. the necessity of introducing ferrous iron which must be separatedafter-processing, acid pH destruction and thus an attack on thecementedinfrastructures which are sensitive to acidity and, finally,hydroxylation of the hydrocarbides which may be contained, together withthe phenols, in the water to be purified. This disadvantage is clearlyobserved in the treatment of effluent from refineries which may contain,in addition to the phenols, between 5 and 50 ppm of hydrocarbides. lnthis case, if there are employed those quantities of reagents which arejust necessary for the destruction of the phenols a surprising increasein the concentration of the latter is observed. During the experimentswhich resulted in the elaboration of the process constituting thesubject of the invention, it was found that this increase in the phenolconcentration was genuine and that it was due to the hydroxylating powerof the reagent l-LO, Fe In order to achieve complete purification, it isthus necessary to add oxidizing reagent in a quantity such that it wouldbe sufficient to hydroxylate all the reactive hydrocarbides and then todestroy the phenols thus formed and those initially present. Thisinvolves a consumption of reagent which may attain to 200 times thatforeseen.

All these disadvantages have made it necessary to seek a novel processhaving the following features and advantages: 3

complete degradation of phenols in all concentrations by opening thearomatic cycle functioning with a catalyst,

and at a pH which is sufficient not to attack the treatment tanksabsence of secondary reactions (hydroxylation).

There has been found a novel process for the purification of effluentpolluted by phenol, based on the exceptional oxidizing power of theanion HSO According to one object of the invention, the oxidizingreagent is a member of the group constituted by monopersulphuric acid.

COOH

According to a further object of the invention, and anion HSO; may beutilized in various forms a. aqueous solutions in which themonoperoxysulphuric anion is associated with ammonium, potassium orsodium ions and H80, and H*;

b. crystallized salt or a mixture of salts the active principle of whichis monoperoxysulphate of potassium HKSO c. aqueous solutions containing,in addition to the oxidizing anion, H and H80; ions and molecules ofll,0,, but free from metallic cation.

According to a variant of the invention, the said solutions contain l to70% by weight of H50; and up to by weight of H,O,.

These various oxidizing reagents may be obtained by the reaction ofhydrogen peroxide on oleum, sulphuric acid, or sulphuric chlorhydrin, orby the hydrolysis of dipersulphates 8,0,.

The mechanism concerned in the reaction affording the destruction of thephenolated impurities is complex and depends on. the composition of theoxidizing solution employed and on the proportion of reagents. On usinga solution of monoperoxysulphuric acid analogous to the solution (c)mentioned hereinabove, a study of the reaction obtained permits theestablishment of a mechanism in three phases According to the firstphase, there are formed diphenols or their semi-quinonic derivatives(this latter hypothesis is the most probable).

H2O L/ If g ,l

cls-cls mueonie acid lunmrlc acid the diphenols (pyrocatechol,hydroquinone), resorcinol and the cresols which, with simple phenol, arethe phenolated impurities most frequently encountered in aqueousindustrial effluent the reaction mechanisms are analogous to thosedescribed with reference to C,H,OH.'

This very thorough degradation involves the utilization of a relativelylarge proportion of oxidizing reagents relative to the phenol to bedestroyed however, this proportion depends also on the type of oxidizingreagent selected in all .cases, at least one mole of H; per mole ofphenol is necessary.

With a solution of type (a), it is to be admitted that, if the oxygen isadded all at once", it will be necessary to employ a quantity of reagentsuch that the molar ratio R HSO;/C H,OH B 50 in order to obtain totalpurification in a sufficiently short period of time. The reaction timewill be the shorter in proportion as the reagent excess is larger thus,if R 240, a solution containing 50 mg/] of phenol will be purified in 5minutes. However, for reasons of economy, it is possible to operate in aplurality of steps first of all, treatment is effected with a reagentratio 2 1, preferably near to 3 in a short period of time, a veryconsideration diminution in the phenol content isachieved there is theneffected a further addition of oxidizing reagent, in such I manner thatR calculated on the fresh phenol concentration is higher than or equalto 50, and so on until total disappearance of the phenol is achieved ingeneral, a treatment employing two oxidizing additions alone issufficient.

The oxidizing solutions of type (c) are more reactive and thedestruction of the phenol may be completed by operating in a singlestage with a relatively small proportion of monoperoxysulphuric acid,such that the ratio R H80 C l-[ 0H is equal to 7.

According to a variant of the invention, there is introduced into theresidual waters an association of reagents which is capable of producingthe monopersulphuric l-lSO; anion, the said association beingconstituted by a compound which is a generator of active oxygen in amixture with sulphuric acid, oleum or sulphuric chlorhydrin. The activeoxygen generating compound is selected from the group based on hydrogenperoxide. In addition to this compound, the mineral or organichydroperoxidates, such as the perborat es, alkaline percarbonates,perpyrophosphates,-

urea peroxide, and also the alkaline and alkaline-earth mineralperoxides constitute active oxygen generating compounds which are ofsignificance to the invention.

The process utilizing this reagent obviates the disadvantages of theprocesses mentioned in the description of the prior art and possesses,in contradistinction thereto, all the properties indicated hereinabove.

The mode of carrying into effect is extremely simple, the treatment iseffected at ambient temperature and it suffices tomix the oxidizingreagent with the efiluent, observing a pH higher than 7, whatever thesource of the oxidizing reagent utilized and preferably close to 9 10.The disappearance of the phenols is generally obtained rapidly.

The process of the invention makes it possible to treat effluents thephenol concentration of which ranges between 0.1 mg/l and 20 g/l.

The HSO, anion may be introduced on a single occasion only or on severaldifferentoccasions. It has been found that the introduction of the H80;anion several times permits the achievement of a diminution in thequantities of oxidizing agent employed.

The novel process described has, relative to that involving the use ofhydrogen peroxide, the considerable I advantage that it is not limitedby the secondary reacwell known, but what is concerned is a mixture ofaro-' matics and aliphatics. The aromatic fraction is thus capable ofbeing hydroxylated.

The influence of the hydrocarbides, in this precise case, has no morethan a slowing-down" significance which may be compensated-for by aslight increase in the reagent excess. Thus, employing an aqueoussolution of H80; ion at a pH of 9 l total purification is achieved,without secondary reactions, with R ISO, in 90 to 120 mn. A 120 ratioaffords the same result, but in 3 to 4 hours. The hydrocarbide contentmay vary between 5 and 20 for example 30 ppm, without greatlyinfluencing the result. On the other hand, the employment of hydrogenperoxide in accordance with the principle of the Fenton reactionrequires for treatment as complete as this, the utilization of a reagentexcess which varies with the hydrocarbide content, since itis necessaryto take account of secondary reactions. Thus, if R H O,/phenol, thefollowing values must be attributed to this ratio R 600 for a solutioncontaining 1 mg/l phenol and 25 mg/l hydrocarbides R 190 for a solutioncontaining 1 mg/l phenol and mg/l hydrocarbides R 120 for a solutioncontaining 1 mg/l phenoland 5 mg/lhydrocarbides R 10 for a solutioncontaining 1 mg/l phenol without hydrocarbides..

. The results set forth hereinabove, and alsothose of the examples, havebeenmonitored by the amino antipyrine analytic method.

' The limit of sensitivity under the test conditions in a few hundredthsof a ppm of phenol. If this control produces-a zero result, it may beaffirmed that the effluent treated contains no more phenol, polyphenolsor quinones.

Some examples which are intended to illustrate the invention are givenhereinbelow, by way of non-limitative example.

Examples I to VII hereinbelow correspond to tests effected withoxidizing solutions of type (a).

EXAMPLE I .complete elimination of the phenol is obtained in .30 minutesat ambientt'emperature such elimination is demonstrated by the aminoantipyrine analysis method which gives a zero result on the treatedsolution. The pH of the reaction is maintained at a value of 9 10 by theaddition of an alkali. Most frequently, the al- ,kaline product utilizedis sodium hydroxide in an aqueous solution.

If a ratio l-ISO '/C,I-I,,OI-I 9.0 is employed, the purificationtreatment is less rapid. In fact, 0.1 mg/l of phenol is revealed after acontact time of 1 hour.

EXAMPLE II The purification is effected of an aqueous 50 mg/l. phenolsolution under the conditions described with reference with Example I,but the quantity of oxidizing reagent is doubled, i.e., 74.8 ml of anaqueous solution equivalent to a 200 g/l monopersulphuric acid. Theratio HSO,/C,I-l -,OH employed is then 240. Purification is total in 5minutes, at ambient temperature.

EXAMPLE Ill Under the conditions of Example I, an aqueous 0.5 mg/lphenol solution is operated upon. The ratio HSO ;/C,H,,OH I20necessitates the addition of 0.38 ml'of the aqueous solution equivalentto a 200 g/l I-I,SO monopersulphuric acid. Disappearance of the phenolis total in 90 minutes.

Smaller ratios involve longer and'more incomplete treatments, ascompared with the amino antipyrine method. Thus, with a ratio of 90, 0.1mg/l of phenol remains after 4 hours.

EXAMPLE IV In this example, there is described 'a purification operationeffected on an industrial effluent discharged from a petrol refinery.The said effluent contains 1.5 mg/l of phenol and 20 mgl/ of a mixtureof aliphatic and aromatic hydrocarbides.

The results are identical with those of Example III, but the presence ofhydrocarbides requires an increase of the ratio I-ISO 'IC I-I OH up to180.

A 120 ratio results in purification which is. equally I complete, but in3 hours to 4% hours, the hydrocarbide content varying between 5 and 20mg/l.

EXAMPLE v' A liter of solution containing 1.5 g of phenol per I080 ml ofan aqueous solution containing the monopersulphuric anion at aconcentration equivalent to'200 g/l of I-I,SO i.e., a ratio HSQS'IC HOI-I 120, is treated.

The pH is maintained at 9 10 by the addition of 400 g/l of caustic soda.Total purification, i.e., purification affording anegativeamino-antipyrine'dosage reaction, is obtained in 60 minutes.

EXAMPLE VI 1 liter of solution containing 50 mg/l of phenol per 0.95 mlof peroxymonosulphuric anion solution and containing the equivalent of200 g/l of H is treated this corresponds to a ratio HSO,f/C,H OI-I 3.

After 30 minutes of contact at ambient temperature, the amino antipyrineanalysis shows that there remains no more than 0.6 mg/l of phenol. Thereis then added 0.46 ml of oxidizing solution (HSO IC H OI-I 120) andafter minutes total elimination of the phenol has been achieved.

The total consumption of oxidizing reagent is only 1.4 ml of solutionper liter of effluent to be treated.

EXAMPLE VII The table given hereinbelow will make it possible toappreciate the reactivity of the H80; ion relative to varioussubstituted phenols. v

Treatment is effected'at pH 10 with a ratio HSO 'IC H .,OH =7; of thesolutions containing 25 ppm (parts per million) of phenol, orthoormeta-.cresol. The elimination of the phenols is measured by aminoantipyrine analysis. The results are expressed as a percentage of phenolremaining after a time t( in minutes) t m. phenol o.-eresol m.-cresolEXAMPLE VH1 ashram" By means of a monopersulphuric acid solution of typec, containing 525 g/l of H.80 there is treated an aqueous refineryeffluent containing 1.5 ppm of phenol and reducing products inquantities such that the oxygen chemical requirement is of the order of100 to 200. Operation is effected at pH 10 with a ratio of reagentHSOf/CJ-QOH 100. The destruction of the phenol is followed by aminoantipyrine dosing.

After 25 m, there remains no more than 0.5 ppm of phenol After 18 m,there remains no more than 0.2 ppm of phenol a After 120 m, thereremains no more than 0.1 ppm of phenol.

After 180 m, there remains no more than 0.0l ppm of phenol What we claimis; 55

l. A process for the complete purification of industrial effluentpolluted by phenolated impurities by conversion of said impurities bythe action of an oxidizing reagent containing the H80, anion, comprisingmixing with-said industrialefiluent an amount of said HSO," anionsufficient to substantially completely destroythe aromatic structure ofsaid phenolated impurities present in said effluent,'said sufficientamountcomprising at least one mole of H80; per 'mol'e'ofphenol. 65

2, A purification process according to claim 1, wherein the oxidizingreagent is monopersulphuric acid or its salts.

3. A purification process according to claim 1, wherein the oxidizingreagent is an aqueous solution containlng the H; anion and additionallycontaining Nl-If', HSO; ions and, optionally, alkaline cations.

4. A purification process according to claim 1, wherein the oxidizingreagent is an aqueous solution containing the H80; anion andadditionally containing hydrogen peroxide and Hi HSO, and SO, ions.

5. A purification process according to claim 1, characterized in thatthe oxidizing reagent is a salt or a mixture of salts the activeprinciple of which is monoperoxysulphate of potassium HKSO,,.

6. A purification process according to claim 1, wherein there isintroduced into the residual waters an association of reagents capableof engendering the peroxymonosulphuric H50 anion.

7. A purification process according to claim 6, wherein the associationof reagents is constituted by an active oxygen generating compound mixedwith sulphuric acid, oleum or sulphuric chlorhydrin.

8. A purification process according to .claim 6, wherein the activeoxygen generator is a member of the group constituted by hydrogenperoxide, the mineral or organic hydroperox'ides such as the perborates,alkaline percarbonates, the perpyrophosphates, urea peroxide, thealkaline and alkaline earth mineral peroxides.

9. A purification process according to claim 1, wherein the treatment ofthe effluent is effected at a pH higher than 7.

10. A purification process according to claim 1,

wherein the treatment is effected at ambient temperature.

11. A purification process according to claim 3, wherein the treatmentis effected, utilizing a reactive H 80 phenol molar ratio close to 50.

12. A purification process according to claim 4, wherein the treatmentis effected utilizing a reactive H 80 phenol-molar ratio close to 7.

13. A purification process according to claim ,1, characterized in thatthe H80; anioniis mixed with said effluent in one stage.

14. A purification process according to claim 1, characterized in thatthe H80; anion is mixed with said effluent in plural stages.

15. A process according to claim 14, characterized in that thequantities of H80 anion are 3 moles per mole of phenol to be oxidizedfor the first addition and at least 50 moles per mole of phenolcalculated on the residual phenolic content after the first treatmentfor the following addition.

16. A purification process according to claim 1, wherein the phenolconcentration of the effluent to be treated ranges between 0.1 mg/l and20 g/l.'

17. A purification process according to claim 1, wherein the pollutantphenol is a dihydroxybenzene, such as pyrocatechol, resorcinol andhydroquinone.

18. A purification process according to claim 1, wherein the pollutingphenol is a methylphenol memberof the group constituted by o.-cresol,m.- cresol and p.-cresol.

* t =r a s

2. A purification process according to claim 1, wherein the oxidizingreagent is monopersulphuric acid or its salts.
 3. A purification processaccording to claim 1, wherein the oxidizing reagent is an aqueoussolution containing the HSO5 anion and additionally containing NH4 ,HSO4 ions and, optionally, alkaline cations.
 4. A purification processaccording to claim 1, wherein the oxidizing reagent is an aqueoussolution containing the HSO5 anion and additionally containing hydrogenperoxide and H , HSO4 and SO4 ions.
 5. A purification process accordingto claim 1, characterized in that the oxidizing reagent is a salt or amixture of salts the active principle of which is monoperoxysulphate ofpotassium HKSO5.
 6. A purification process according to claim 1, whereinthere is introduced into the residual waters an association of reagentscapable of engendering the peroxymonosulphuric HSO5 anion.
 7. Apurification process according to claim 6, wherein the association ofreagents is constituted by an active oxygen generating compound mixedwith sulphuric acid, oleum or sulphuric chlorhydrin.
 8. A purificationprocess according to claim 6, wherein the active oxygen generator is amember of the group constituted by hydrogen peroxide, the mineral ororganic hydroperoxides such as the perborates, alkaline percarbonates,the perpyrophosphates, urea peroxide, the alkaline and alkaline earthmineral peroxides.
 9. A purification process according to claim 1,wherein the treatment of the effluent is effected at a pH higher than 7.10. A purification process according to claim 1, wherein the treatmentis effected at ambient temperature.
 11. A purification process accordingto claim 3, wherein the treatment is effected, utilizing a reactiveH2SO5/ phenol molar ratio close to
 50. 12. A purification processaccording to claim 4, wherein the treatment is effected utilizing areactive H2SO5/ phenol molar ratio close to
 7. 13. A purificationprocess according to claim 1, characterized in that the HSO5 anion ismixed with said effluent in one stage.
 14. A purification processaccording to claim 1, characterized in that the HSO5 anion is mixed withsaid effluent in plural stages.
 15. A process according to claim 14,characterized in that the quantities of HSO5 anion are 3 moles per moleof phenol to be oxidized for the first addition - and at least 50 molesper mole of phenol - calculated on the residual phenolic content afterthe first treatment - for the following addition.
 16. A purificationprocess according to claim 1, wherein the phenol concentration of theeffluent to be treated ranges between 0.1 mg/l and 20 g/l.
 17. Apurification process according to claim 1, wherein the pollutant phenolis a dihydroxybenzene, such as pyrocatechol, resorcinol andhydroquinone.
 18. A purification process according to claim 1, whereinthe polluting phenol is a methylphenol member of the group constitutedby o.-cresol, m.-cresol and p.-cresol.